Congo or Zaire

The only river on the planet which flows in both the northern and
southern hemispheres.

The
Congo actually emerges from the Lualaba River which rises from a
plateau some 1,418 metres above sea level. The Lualaba joins
with
the Lufira and the Luvua Rivers. The Luvua is dervived from
the
Luapula (also known as the Chambezi) which is also considered to be a
headstream of the Congo. Many dramatic waterfalls exist along
the
Luvua and the commbined rivers are joined by the Lukuga which flows in
from Lake Tanganyika. At 80 km downstream, a long navigable
section ends as the the "Portes d'Enfer", a particularly wild section
of rapids, generates copious amounts of white water. The
rapids
run for some 120 km, at which point another navigable section kicks in
and lasts for another 300 km until it reaches the Stanley
Falls.
After the seven sections of the Stanley, the river officially becomes
the Zaire and is then navigable for 1600 km. Lower down the
river
is as much as 15 km wide. Navigability ends with the Stanley
Pool, across which the cities of Kinshasa and Brazzaville face each
other. After the Pool comes the 32 sections of the
Livingstone
Falls as the river cuts through the Crystal Mountains. It
then
broadens out into an estuary, part of which forms a large whirlpool
known as the "Devil's Cauldron". The river then splits into
two
channels around Matoba Island followed by the delta. Beneath
the
surface, the river has carved a canyon which extends far out to
sea.

The
Nile is the main outlet for Africa's largest lake - Lake Victoria - so,
even at its source it is a substantial river. It drops to
lake
Albert, and then again down to the Sudan where it is known as Bahr el
Jebel. For some 500 kilometres it runs through Sudanese swamp
land until it reaches Lake No. From there it becomes the
clear
running White Nile until it converges with the Blue at
Khartoum.
From thence, it becomes the Nile proper for the remaining 3000 km to
the Mediterranean Sea. During the wet season, the Blue
provides
about 70% of the Nile's water, but as the dry season comes, it is the
White that keeps the river flowing.

The river pours into
Lake Nasser and is utilised for power at the massive Aswan Dam at the
lake's exit point. From there, it runs through desert all the
way
to Cairo. The Nile valley is only about 1.5 km wide
throughout
most of this stage, before widening to as much as 20 km at the delta,
passing the Great Pyramids just south of Cairo. In the delta,
criss-crosssed by multiple channels and sub-tributaries, the river is
actually known as two separate branches - the Damietta and the
Rosetta.

Being the mother of humanity, it is perhaps not
surprising to realise that it is the most studied river on the
planet. Water level and other records have been kept since
711 AD.